The present invention is an improvement in the known process whereby a textile material is sized by impregnating it with a solvent solution of a resinous sizing material. The invention also relates to an improved sizing resin composition and to the textile yarns sized with it.
Most commercial sizing of textile yarns is done at present with aqueous solutions or dispersions of substances such as starch, gelatin, casein, or water-soluble or dispersible polymers, for example, polyvinyl alcohol, cellulosic polymers, and other such organic polymers. Aqueous systems such as these have a number of disadvantages including sensitivity of the sized yarns to humidity, high energy requirements, and the problem of disposal of a contaminated waste water stream from the desizing process after weaving.
It is also known to size yarns with a chlorinated solvent solution of a soluble polymer such as a chlorinated polyolefin of which chlorinated polyethylene, chlorinated ethylene-propylene copolymer, copolymers of vinyl chloride and vinylidene chloride, polyvinyl chloride, and chlorinated rubber are examples. Such processes are described by Pritchard, U.S. Pat. Nos. 2,978,362; by Armour et al., 3,228,791; and by Case et al., 3,476,504. However, when these polymers are of low crystallinity as they typically are, the sized yarns tend to be tacky and cause problems in weaving because the yarns stick to one another and exhibit high friction with respect to parts of the weaving apparatus resulting in deterioration of fiber lay-down and warp breaks.